How to identify thermocouple and nickel chromium nickel silicon thermocouple is what is the method of the cathode _ instrument

Thermocouple linearity, thermoelectric emfs is bigger, so can be used for oxidizing, inert atmosphere. But k type thermocouple cannot be directly used for sulfur, reducing or at high temperature reduction, oxidation atmosphere and vacuum alternately, is also not recommended for people with weak oxidizing atmosphere. Then we will say so the identification way of thermocouple is negative, and other types of thermocouple is negative. Thermocouple is very nickel-chromium alloy (containing 10% chromium kp) , the negative is extremely containing silicon 3% nickel silicon alloy ( kn) 。 Therefore, with the magnet can be easily identified thermocouple of positive and negative pole. As for the other thermocouple is negative to distinguish is also very simple, such as nickel and chromium - Nickel silicon thermocouple, it has obvious color to distinguish the two root silk, there is a green, one is gray, green is positive, if is the thermocouple wire, you can use a small magnetic materials, on the cathode surface, the root is the gray silk, attractive if it is negative. Nickel chrome - Nickel silicon thermocouple ( K type thermocouple) Is above 500 ℃ temperature area as use cheap metal thermocouple, its usage is the sum of other metal thermocouple. The anode ( KP) In the name of the chemical composition is: Ni: Cr material 90:10, the cathode ( KN) The chemical composition is: Ni: Si material 97: its use temperature range for - 20 ~ 1100 ( 1300). ℃. K type thermocouple has good linearity, large thermoelectric emfs, high sensitivity, good stability and uniformity and oxidation resistance is strong, and the advantages of cheap, can be used for oxidizing, inert atmosphere. K type thermocouple cannot be directly used for sulfur, reducing or at high temperature reduction, oxidation atmosphere and vacuum alternately, is also not recommended for people with weak oxidizing atmosphere. Besides the nickel chrome - The chemical composition of a nickel and silicon thermocouple: nickel chrome - Nickel silicon ( Nickel aluminum) Thermocouple ( Index number is K) Is very nickel-chromium alloy (containing 10% chromium KP) , the negative is extremely containing silicon 3% nickel silicon alloy ( KN) 。 Based on this feature, use the magnet can be easily identified thermocouple is negative. Its characteristic is, the use of wide temperature range and high temperature performance is stable, the thermoelectric emfs approximate linear relationship with the temperature, low price, therefore, it is the use of a thermocouple, nickel chromium - Nickel silicon thermocouple, K type thermocouple for continuous use in oxidizing and inert atmosphere. Short-term use temperature is 1300 ℃, the long-term use of temperature is 1100 ℃. After choosing high quality K type thermocouple can be used as a standard, to dividing work with nickel and chromium - Base metals such as nickel silicon thermocouple, add the thermocouple on the poles yttrium metal and magnesium, oxidation resistance can be further improved, high temperature can reach 1300 ℃. In order to give full play to the advantages of cheap metal prices cheaper, at the same temperature, it can be installed more than several thermocouple, using its high sensitivity and thermoelectric properties of approximate linear characteristic, achieve the purpose of accurate measurement, the K type thermocouple is oxidation resistance strong base metal thermocouple. Not appropriate in a vacuum atmosphere, carbon, sulphur and alternating oxidation and reduction under the atmosphere of bare wire. When oxygen tension is low, nickel and chromium in the chrome will be the optimal oxidation ( Also known as green corrosion) , has brought great changes in the thermoelectric emfs. But the influence of metal gas? Therefore, using metal thermocouple protection tube. How the points of the thermocouple is negative first nickel chrome - Nickel silicon two root of thermocouple wire has obvious distinguish color, there is a green, one is gray, green is positive, if is the thermocouple wire, can use a small magnetic materials, on the cathode surface, which root silk top is grey, attractive if this is the negative? Now with nickel and chromium - Nickel silicon thermocouple spot many, but a lot of users in the nickel chrome - Thermocouple replaced nickel chrome - nickel silicon Nickel aluminum thermocouple. But there are still some old customers or abroad to use nickel chrome - Nickel aluminum thermocouple. The chemical composition of two kinds of thermocouple, though different, but its thermal properties are the same, using the same indexing table.